Adrien dawans



Jan. 12, 1932. A, DAWANS DEVICE FOR ROASTING AND AGGLOMERATING ORES Filed March 18, 1950 I a Ma a/Z a);

flZrz-n, Jam/cans Patented Jan. 12, 1932 PATENT orelce ADRIEN DAWANS, OF BRUSSELS, BELGIUM DEVICE FOR ROASTING AND AGGLOMERATING ORES Application filed March 18, 1930, Serial No. 436,811, and in Belgium April 6, 1929.

It is known to produce the agglomeration of ores which are in a granulous and porous form and contain a suitable proportion of combustible materials by simply passing a draught or blast of air through the mass for maintaining the combustion.

These granulous products are generally arranged in containers the base of which is formed by a grill and communicates with a suction fan. The combustion is commenced at the upper part by any means and then continues by employing as fuel the heat generating elements contained in these products. 7 This prior process presents the disadvantage that the lower layers are increasingly heated by the passage of the gases produced by the combustion of the upper layers, and by the heating of the air supporting the combustion passing through the upper layers. Consequently the said lower layers are subj ected to a much higher temperature and pro duce compact and vitrified agglomerates, which do not give good results when these oxides are reduced on account of their lack of porosity.

' The object of the present invention is to remove these disadvantages by employing a movable bed plate on which the fusion is effected, the displacement of this bed plate being capable of being effected at an equal speed and in the opposite direction to the propagation of .the heat.

According to the invention the materials to be treated are poured at a certain distance in front of the melting zone and the treated materials are removed at a certain distance behind the said zone, the combustion being produced by a supply of air obtained through the materials situated on the movable bed plate. I

This arrangement permits a reheating of the air to be obtained at a substantially fixed temperature by passage through the agglomerated products situated upon the bed plate and the materials to be treated to be heated at a substantially fixed temperature, this heating being effected by the passage of the burnt'gases through the mass of non treated products.

According to the invention the materials are automatically loaded and discharged by bringing them upon the bed plate by gravity through a duct leading to a loading hopper, the automatic removal of the treated materials being effected for example by forming the movable bed plate of a drum.

The accompanying drawing indicates by Way of example and in a nonlimiting manner one embodiment of the invention. The invention extends to the various original features which the arrangement shown comprises.

The figure shows a perspective view with part in section of a device constructed according to the invention.

A duct leading from a loading hopper, not shown, receives the materials to be treated and leads into the upper part of the drum 3 lined with refractory materials and extending over the whole length of the latter. This drum 3 is provided with side plates 3aalso lined with refractory materials, so as to form with a fixed roof 4 a duct of such section that the materials fill it completely.

On account of the contraction which the materials treated generally undergo, it is necessary to reduce the section of the channel occupied by these treated materials in proportion to the contraction undergone.

Pipes such as 5 leading from a suction fan terminate at the foot of the duct 2 and are arranged over the whole length of the drum. A valve is provided in each pipe 5 so as to permit the section of the pipe to be regulated separately.

The duct formed by the drum and the roof 4 is made fluid tight on the one'hand by elastic and incombustible oints 6 made for example of asbestos, which are secured upon the space between the drum and the said roof by the effect of the suction and on the other hand by an elastic blade 6a which presses against the end of the drum but nevertheless permits the passage of the hard materials attached on the bed plate without danger of fracture.

In order to compel air to pass through the materials situated on the bed plate and not the materials situated in the duct 2, the invention provides for this duct to be closed for example by means of a double hopper not shown, situated at the upper part of the said duct. v r

In order to start the oven, the duct 2 and the top part of the drum are filled with untreated materials and the fan is started and the combustion commenced in any manner, for example by means of chips of wood.

Once the combustion has been started it spreads into the whole mass and, when the latter has reached a given Zone 2a, the drum is rotated in the direction of the arrow X at a speed such thatthe combustion zone 2a re mains substantially fixed with respect to the roof 4. The propagation of the combustion is supervised through windows, not shown.

The agglomerated materials become detached from the drum at a given moment under. the ell'ect of the inclination and of the rotation of the drum, and new materials are fed on to the bed plate by gravity through the duct 2.

The operation and the temperature of the combustion zone are regulated for example by the amount of combustible materials contained in the materials to be treated. According to the amount of combustible elements the desulphuration.

Moreover the amount of air drawnin by the fan is such that it produces the complete combustion of these materials.

Undernormal working conditions, the air drawn in is heated through the products treated, which are situated on the bed plate in such a manner as to recuperate a part of the heat carried away by these products and to permit the air to be heated to a substantially fixed temperature, since the quantity of materials treated through which it passes is approximately constant. I

Moreover the gases produced by the combustion give up a partof their heat to the untreated materials so that the latter reach the combustion zone with a substantially constant temperature.

In this way the operation of the combustion zone does not undergo variations and the products obtained. are always of exactly the same chemical and physical constitution.

Itis to be noted that the recuperation of heat is thus eilected in two very distinct ways, on account of the variations in specific: heats one by the recuperation by the air of the heat contained in the products treated, the other by the recuperation by the untreated products of the heat in the gases from the combustion. Consequently for a given drum, the length of the zone occupied by the products situated on the latter being constant, it is possible to vary. the operation of the combustion zone by changing the situation of the latter on-the bed plate, which alteration may be obtained if desired by a momentary variation in the speed of rotation of the drum.

Moreover, according to the degree of fusibility of the product to be treated and also of the treatment to which it is to be subjected, the amount of heat recuperated is varied by increasing or reducing the zone on which theheat exchanges take place.

For this purpose the invention provides for example for the length of the zone occupied by thefproducts situated on the drum to be increased or reducedby giving this drum a diameter which is suitable for each product to be treated. 1

' This layer of fine materials is only partly attacked by the fusion on account of its small degree of porosity, and there always remains on the otherpart of the drum a thin layer of dust which assists the molten materials to fall and prevents caking and choking,

The device described above is particularly suitable for the treatment of pyrites on blast furnace duct. v

VVhat I claim is 1. Apparatus for roasting andvagglomerating ores, comprising a movable drum, means for feeding the ores onto the periphery of the said drum, discharge means for the treated ores positioned along the circumference of the said drum, means between the feeding zone and the discharge zone for combusting the ores, and means for producing a draught of air in a direction opposite to the displacement of the said drum.

2. Apparatus for roasting and agglomerating ores, comprising a movable drum, lateral plates on the said drum, a stationary, partially circular vault surrounding the said drum to form a conduit encompassed by the drum, the. plates, and the circular vault, a hopper for feeding the ores onto the periphery of the drum, discharge means for the treated material s positioned on theperiphery of the drum, means between the feeding zone and the discharge zone for combusting the materials. and ventilating means producing a current of air in a direction opposite to the nature.

ADRIEN DAVVANS. 

